Dual bobbin assembly for coils

ABSTRACT

A bobbin for a motor coil is constructed with a flange having a lead wire retainer extended therefrom. The retainer is in the form of a tab having spaced fingers which present pockets for capturing the lead wires. The retainer has an opening through which the lead wires are passed for strain relief. A complemental member with complemental fingers opposes the tab to clamp the wires.

Unite States Patent [191 Anderson et a1.

1 1 DUAL BOBBllN ASSEMBLY FOR COILS [75] Inventors: David S. Anderson;Lawrence F.

Kottke, both of McHenry, 111.

[73] Assignee: Original Equipment Motors Inc.,

Crystal Lake, 111.

22 Filed: on. s, 1973 21 App1.No.:404,377

[52] US. Cl 336/90, 310/194, 336/192, 336/198 [51] llnt. C1. H011 15/10[58] Field of Search 336/192, 198, 208, 90; 242/1252; 310/194 [56]References Cited UNITED STATES PATENTS Wahl 336/192 x [111 3,843,946 [4Oct. 223, 1974 3,191,135 6/1965 Hazelquist 336/198 X 3,453,575 7/1969Davis 336/198 X 3,524,156 3/1970 Horbach .1 336/208 3,609,616 9/1971Dumeige 336/208 X Primary Examiner-Thomas J. Kozma Attorney, Agent, orFirm-Kinzer, Plyer, Dorn & McEachran [57] ABSTRACT A bobbin for a motorcoil is constructed with a flange having a lead wire retainer extendedtherefrom. The retainer is in the form of a tab having spaced fingerswhich present pockets for capturing the lead wires. The retainer has anopening through which the lead wires are passed for strain relief. Acomplemental member with complemental fingers opposes the tab to clampthe wires.

15 Claims, 12 Drawing Figures 1 DUAL BOBBIN ASSEMBLY FOR COILS Thisinvention relates to the construction of bobbins used in electricmotors, both single coil and dual coil.

In a dual coil electric motor two bobbins are arranged in co-axialrelation, each bobbin being wound with many turns of small diametercopper wire. Two lead wires are spliced to the ends of each coilwinding, merely by twisting and securing (e.g., soldering) the wireends. Conventionally, to prevent separation of the spliced wire ends,the splices are made at a low point on the coil circumference, the leadwires are brought to the top of the bobbin, tape is wrapped about thecircumference of the coil, and the free ends of the lead wires are thenextended through grommet-protected openings in the cup-shaped metalframes which house the two bobbins. Nonetheless, the anchor for theleads is merely the partial capstan effect represented by a partial lapof the lead wires on the outer circumference of the coil winding, nomore than a 180 lap. The same procedures are followed for a single coilmotor.

The primary object of the present invention is to construct the bobbinsso that the lead wires are not only clamped in the bobbins but are benton two turns in different directions, constituting a very effectiveresistance to separation of the spliced ends. Additional objects of theinvention, attained by interfitting wire retainer tabs on the bobbins,are: to anchor the lead wires in a neat, predetermined alignmentcompared to the random, knotty disposition presently involved; toprotect the insulation on the lead wires; to isolate the lead wires frommetal surfaces; to achieve a grommet effect without need for separateattachable grommets, and to effect fixturing of the leads while makingconnections. Another object of the invention is to achieve the sameobjectives in a single bobbin.

In the drawing:

FIG. 1 is a perspective view of the known, prior art construction;

FIG. 2 is a plan view of a motor constructed in accordance with thepresent invention, partly in section;

FIG. 3 is a sectional (cut-away) view of the motor shown in FIG. 2;

FIG. 4 is an elevation of a bobbin constructed under the presentinvention;

FIG. 5 is a section on the line 5-5 of FIG. 4;

FIG. 6 is an elevation on the line 6-6 of FIG. 4;

FIG. 7 is a fragmentary detail view of the retainer or holder on anenlarged scale compared to'FIG. 6;

FIG. 8 is a detail view on the line 8-8 of FIG. 7;

FIG. 8A is a view similar to FIG. 8 showingthe way in which two wireholder tabs interfit;

FIG. 9 is an exploded view showing the manner in which two bobbins arerelated to the frame members of a dual coil motor assembly;

FIG. 10 is a view of a single coil motor incorporating a bobbinconstructed in accordance with the present invention; and

FIG. 11 is an elevation on the line 1l-l1of FIG. 9.

Referring to FIG. 1, perspective view of a dual coil motor of knownconventional form, two coil housings 21 and 22 respectively contain awound bobbin 23 separated for clarity in FIG. 1. The bobbin 23 is ofknown form and the core 24 thereof is wrapped with fine copper wire 25.I

Rotors, not shown, are arranged within the core openings of the bobbininside the housing 21 and 22, being mounted on ashaft 26 constitutingthe driven element of the motor.

In completing the coil assembly, a pair of lead wires 30 for each coilhave ends thereof spliced at 30A and 30B to the ends of the wire winding25 on the bobbin. Such splicing, for reasons to be explained, iseffected at what constitutes the bottom of the bobbin, after which theinsulated lengths of the lead wires are drawn upwardly in snug contactwith the periphery of the coil winding 25. A piece of tape 32 is thenwrapped aobut the coil to cover the spliced ends and to secure the leadwires in place on the winding.

After the bobbin sub-assembly has been completed'in the-fashiondescribed above, that is, after the tape 32 is applied, the bobbin isarranged within the corresponding motor housing. The motor housings aresplit cups, as will be explained in the description to follow.

The lead wires 30 are extended through openings in the top of the motorhousing and grommets 34 are then applied, fitting the openings, toprotect the lead wires from the sharp edges of the openings in the motorhousings through which the lead wires were passed.

The reason for using the tape 32 and for effecting the splices 30A and30B at the locations shown in FIG. 1 is to relieve strain on the leadwires so that the splices will remain intact. Such procedures entailefforts properly to locate the splices and also entail the use of tape32 to say nothing of the time and expense required to apply thegrommets. Moreover, the lead wires in the motor assembly are indisarray. These deficiencies are overcome under the present invention.

A bobbin constructed in accordance with the present invention is.shownin FIGS. 4, 5 and 6, a bobbin 35 of circular form having a pair ofannular flanges 36 and 37 joined by a core or collar 38.

The bobbin 35 may be of molded plastic material knownin the art, and oneof the circular flanges thereof is molded to present a radiallyprojecting lead wire retainer 40 of tab form. As shown in FIG. 5, theinner face or surface of the tab 40 lies in the plane of whatconstitutes the inner wall of the related bobbin flange 37. A slot 43 isformed in the bobbin flange 37. The slot 43 opens at the opposite sideof the related bobbin flange as shown in FIG. 6.

The outer side of the tab 40, FIGS. 6, 7 and 8, is molded to present aplurality of integral flexible fingers collectively identified byreference character 45 in FIG. 6. Each of the fingers 45 projectsaxially and is elongated parallel to a diameter of the bobbin.

The spaces between the fingers afford pockets collectively identified byreference character 46 in FIG. 6. These are four fingers and fourpockets as will be described, selected pockets serving to capture thelead wires and the related fingers being effective to crimp the leadwires.

FIGS. 7 and 8 show the tab 40 at a greatly enlarged scale. The tabincludes a base 48 representing the radial extension of the relatedflange as 37 and as will be evident in FIG. 8 there are, for the dualcoil bobbins under consideration, four fingers, 45-1, 45-2, 45-3 and45-4, the fingers projecting at right angles to the plane of the base48, which is to say that the fingers 45 project axially from the outerwall of the bobbin flange 37.

As will be evident in FIG. 8, the pockets 46 referredof the pocketbetween fingers 45-1 and 45-2. The.

pocket between fingers 45-2 and 45-3 is wider than a wire, equally trueof the open-ended pocket to the left of finger 45-1.

Referring to FIG.- 4, lead wires B (black) and G (grey) have thebareends thereof connected as by a twist T and solder (or crimp)respectively to the free ends of the copper .winding representing thecoil of the bobbin shown in FIG. 4. This splice orconnection of the leadwires to the coil may be accomplished at the tab end of the bobbin andneed notbe effected at the bottom of the coil in the manner of the priorpractice shown in FIG. 1. I

The connections at T are made after. the lead wires B and G areextended'through the clearance hole 43, FIG. 4, having the effect offixturing, repeated for each bobbin, FIGS. 3 and 9. 1

Prior to completing the motor assembly, the lead wires are press fittedinto two alternate pockets 46 of the related retainer tab, the twosquared pockets 46-2 and 46-4 as best shown in FIG. 8A.

' Slot 43 is located at the root of the pockets, FlG. 7, thepocketsbeing numbered like the fingers. It will be recognized that as anincident to passing the lead'wires B and G through the slot 43 andpressing them into the pockets 46-2 and 46-4, two right angle bends aremade in the lead wires. One bend is made, FIG. 9, whenthe lead wire isextended from the periphery of the coil winding into the slot 43 and asecond bend is made when pressing the wire into the tap pocket assignedthereto. From this it will be seen that in arranging a lead wire withina retainer pocket two bends are made therein in different directions, sothat a tug force in tension far beyond any force normally encountered isrequired in order to break or separate the spliced ends of the wires. j

In accordance with standard practice, the bobbins 35 are to be housedbetween complemental cup-shaped frame members 51 and 52, FIG. 3, frame51 being of larger diameter so that frame 52 may be telescoped therein.Referring to FIG. 9, the inner frame members 52 are provided withrespective slots 54 for receiving the retainer tabs 40 of the pairedbobbins 35.

Referring again to FIG. 9, a bobbin 35 is juxtaposed with respect to thecasing or housing 52, the tab being aligned with the receiving slot 54.The receiving slot has a wide (throat) end54A wider than the span of thetab 40, neatly receiving the tab.

The slot 54 is narrowed to a neck at 548 to a width slightly less thanthe span or long dimension of the tab 40 so that the tab 40 has a slightpress fit at the end 548 of the receiving slot 54. These dimensions areof course equal for each bobbin 35 and each frame member 52 having aslot 54. Y

The tabs 40 of two bobbins are so configured that one is the complementof the other and consequently the opposed fingers are self-guiding andinterfit to' trap the lead wires in the pockets. In fact, theconfiguration is such that the lead wires are crimped by wedging forcesas a further resistance to forces that might disrupt the wire splices;the press fit of the tabs in the housing slots 54- is yetfurther-assurance to preserving the splice intact.

Referring to FIG. 8, there is an end finger -4 and three additionalfingers. The fingers have spaced opposed walls which of course definepockets for the lead wires. More specifically, the two pockets 46-2 and464 are .squared off so to speak by opposed parallel inside fingerwalls, 60-61 and.62-63 respectively. These opposed inner walls arespaced apart by a distance just slightly less than the diameter of theinsulated lead wires so that the latter (B and G) may be press fittedtherein after the lead wires are extended through slot 43. Such pressfit maintains the lead wires in a readily identifiable array.

It will be realized that fingers 45-1 and 45-2 are paired to define apocket 46-2 accepting a lead wire; fingers 45-3 and 45-4 are a second,similar pair. At least one of the paired fingers has a sloped outer wallso that thepaired outer walls are convergent proceeding outward(axially) from the base. Thus, finger 45-3, paired with finger 454, hasa sloped outer wall 65. The two fingers in the other pair each have asloped outer wall, 66 and 67 respectively.

Consequently, by presenting an opposing member having fingers withcomplementally shaped walls, the fingers may easily be nested and thewires in pockets 46-2 and 46-4, FIG. 8, may be crimped and retained by apositive force. In a dual coil assembly, the opposing member is the twintab. Thus, as shown in FIGS. 3 and 8A, the fingers of the two tabs 40fit complementally so that one guides the other. More specifically, FIG.8A, finger walls 65 and 66 of the two opposed tabs wedgingly engage oneanother to crimp the two B wires in the respectiveend pockets 46-4 ofthe two retainers 40; the two opposed finger walls 67 wedgingly engageto crimp wires G in the two inside pockets 46-2. The tabs neatly andsnugly fit together.

It will be recognized thatat least one finger defining each pocket ispreferably flexible and has a sloped outer wall so that it may guide andincidentally be wedged inward by a finger of the opposing member, theopposing finger having a complemental slope. The principle of guidingmay be readily recognized by observing the interfit between the fingerswhich house wires G; the principle of crimping may be readily recognizedby considering the way in which the fingers with complemental slopes 65and 66 are efiective to crimp the righthand lead wire B, FIG. 8A. Also,in principle, at least three fingers are required to define two pocketsfor the two lead wires; two of the fingers would therefore be flexiblein the preferred embodiment. In the two coil assembly, the advantage oftwo fully complemented retainer tabs is apparent: only one mold isrequired to shape the bobbins; there is no lefthand or righthand so thattwo bobbins may be juxtaposed with the tabs facing one another, FIG. 8A,as mirror images of one another.

The principle of the invention may be further studied in terms of amotor having a single coil, the motor 75, FIG. 10, having twointerfitting C-shaped frames 76 and '77.

A bobbin identical to 35 described above, having a retainer tab 40, FIG.10, is encapsulated by the housing frames 76 and 77. The tab 40, FIG.10, has the same four fingers 45 described above and the same slot 43.

A rigid die cast cover 78 is staked to frame 77, completing the motorassembly.

Cover 78 is cast with an integral tab 80 constituting the opposingmember for retainer tab 40. Tab 80 is provided with two end fingers orlugs 82 and 84 and an intermediate finger 85 having walls complementalto those presented by the fingers of tab 40, whereby the latter guidethe opposing tab 80 to produce an easy, neat fit and whereby the slopesof the fingers on tab 80 flex the fingers 45, FIG. 9, to crimp the leadwires.

Additional pressure is applied by the skirts of the outer cups on thetwin tabs in still another direction.

From the disclosure in FIGS. and 1 1 it will be realized that the set offingers of the tab and the set of fingers of the opposing member neednot both be flexible, it is enough that selected ones of the tab fingersbe flexible, thereby to guide the fingers of the opposing member whichmay be rigid, comparatively speaking. In this same connection, asalready noted, it is sufficient, in principle, that one finger for eachpocket be flexible to create the incidental crimp or clasp on the leadwire. In a dual coil assembly, however, and since the bobbins are ofinsulating plastic material, all fingers of the mating tabs areflexible.

In any event, when the opposing member is presented and nested withrespect to the tab as 40, both in a dual coil assembly (FIG. 3) and in asingle coil assembly (FIG. 10) the mating fingers capture or encapsulatethe lead wires as B and G on four sides, namely, the foursided pockets.The tab fingers and the root or base of the pocket (e.g. base element48) define three sides and the base of the opposing member completes thefour-sided pocket.

Since the pockets as 46 extend parallel to the plane of the tab base as48, that is, parallel to a diameter of the bobbin, and sinde the leadwires are bent, FIGS. 3 and 9, incidental to being passed through slot43 and then are bent in a second direction incidental to being nested inthe pockets, it will be seen that effective strain relief is achieved bytwo bends to say nothing of the final crimp or squeeze effect whenpress-fitting the wires in the pockets and bending the fingers inwardwhen the opposing member is nested in the pockets.

In view of the foregoing it will be seen that while preferredembodiments have been disclosed, the principles of the invention may beapplied to modified and varied forms.

I claim:

1. In a dual bobbin assembly for a dual coil motor, a pair of bobbinsarranged in co-axial relation, each bobbin having a core to be woundwith a wire and a pair of end flanges attached to the core for retainingthe winding, a flange of each bobbin being provided with a retainer forimmobilizing the lead wires connected to the ends of the related coilwinding, each retainer being the complement of the other and comprising:a radially projecting tab having one axially projecting end finger, andan odd number of additional axially projecting fingers arranged inspaced relation as a set to afford pockets for said lead wires, each ofthe additional fingers having a sloped wall with the fingers on the tabsof the two bobbin flanges in opposed interfitting relation so that thesloped walls of one set of additional fingers wedge on the sloped sidewalls of the other set of additional fingers, thereby to crimp andretain the lead wires disposed in the pockets 2. A dual bobbin assemblyaccording to claim 1, wherein the fingers are elongated parallel to adiameter of the bobbin core and where each tab has a slot formed thereinthrough which the lead wires may be extended, a lead wire so extendedbeing bent in one direction to lay in a pocket and being bent in anotherdirection to be joined to the related coil end.

3. A dual bobbin assembly according to claim 1 wherein the pocketsretaining the lead wires are of a dimension less than the diameter ofthe lead wires so that the lead wires may be press-fitted therein.

4. A dual bobbin assembly according to claim 1 wherein each bobbin ishoused between cup-shaped frame members, one of the frame members havinga slot for receiving the related tab, said frame slot having an entrancethroat of greater width than the tab and having a neck of less widththan the tab to crimp the tab.

5. In a spool-like bobbin for a motor coil, wherein the bobbin has acore on which the coil is wound and a pair of end flanges for retainingthe coil winding, a lead wire retainer tab attached to the periphery ofone flange of the bobbin, said tab having a base with at least threespaced apart flexible fingers projecting therefrom, the spaces betweenthe fingers constituting pockets for capturing lead wires, selected ofthe fingers each having a sloped outer wall and said sloped outer wallsbeing convergent toward one another proceeding outward of the tab base.

6. A bobbin according to claim 5 wherein a slot is fonned in the tab atthe root of the pockets enabling lead wires to be passed therethroughand bent to lie in the pockets.

7. A bobbin according to claim 5 combined with a member opposing theretainer tab, said opposing member having fingers with walls shapedcomplemental to the sloped walls of the fingers on said retainer tabthereby to wedgingly hold the lead wires in the pockets.

8. A bobbin according to claim 6 combined with a member opposing theretainer to clamp the wires in the pockets, said opposing member havingfingers with walls shaped complemental to the walls of the retainerfingers.

9. In a spool-like bobbin for a motor coil, wherein the bobbin has acore on which the coil is wound and a pair of end flanges for retainingthe coil winding, a lead wire retainer tab supported on a flangeperiphery, said tab having spaced, flexible fingers projecting axiallytherefrom and having a length parallel to a diameter of the bobbin, eachfinger having an inner wall and an outer wall, spaces between adjacentwalls of the fingers affording at least two pockets for two lead wires,and selected walls of the fingers being sloped so that the tab fingersmay be used as guides for an opposing member having complemental fingersthereby to encapsulate the wires on four sides.

10. A bobbin according to claim 9 wherein the tab has a slot throughwhich may be extended the lead wires attached to the ends of the coil.

11. A bobbin according to claim 9 wherein the tab fingers are flexible.

12. A bobbin according to claim 10 whereinthe tab fingers are flexible.

13. In a bobbin for a, motor coil, the bobbin having a core to be woundwith a wire and having a pair of special end flanges attached to thecore for retaining the winding: a wire retainer tab attached to one ofthe flanges and lying substantially in the plane thereof, said tabhaving spaced fingers defining pockets for receiving lead wires eachhaving end attached to a respective end of the coil winding, saidpockets extending parallel to the plane of the tab, said tab having aslot therein communicating with the root of the pockets whereby the leadwires attached to the coil winding may be bent in four-sided pockets.

1. In a dual bobbin assembly for a dual coil motor, a pair of bobbinsarranged in co-axial relation, each bobbin having a core to be woundwith a wire and a pair of end flanges attached to the core for retainingthe winding, a flange of each bobbin being provided with a retainer forimmobilizing the lead wires connected to the ends of the related coilwinding, each retainer being the complement of the other and comprising:a radially projecting tab having one axially projecting end finger, andan odd number of additional axially projecting fingers arranged inspaced relation as a set to afford pockets for said lead wires, each ofthe additional fingers having a sloped wall with the fingers on the tabsof the two bobbin flanges in opposed interfitting relation so that thesloped walls of one set of additional fingers wedge on the sloped sidewalls of the other set of additional fingers, thereby to crimp andretain the lead wires disposed in the pockets.
 2. A dual bobbin assemblyaccording to claim 1, wherein the fingers are elongated parallel to adiameter of the bobbin core and where each tab has a slot formed thereinthrough which the lead wires may be extended, a lead wire so extendedbeing bent in one direction to lay in a pocket and being bent in anotherdirection to be joined to the related coil end.
 3. A dual bobbinassembly according to claim 1 wherein the pockets retaining the leadwires are of a dimension less than the diameter of the lead wires sothat the lead wires may be press-fitted therein.
 4. A dual bobbinassembly according to claim 1 wherein each bobbin is housed betweencup-shaped frame members, one of the frame members having a slot forreceiving the related tab, said frame slot having an entrance throat ofgreater width than the tab and having a neck of less width than the tabto crimp the tab.
 5. In a spool-like bobbin for a motor coil, whereinthe bobbin has a core on which the coil is wound and a pair of endflanges for retaining the coil winding, a lead wire retainer tabattached to the periphery of one flange of the bobbin, said tab having abase with at least three spaced apart flexible fingers projectingtherefrom, the spaces between the fingers constituting pockets forcapturing lead wires, selected of the fingers each having a sloped outerwall and said sloped outer walls being convergent toward one anotherproceeding outward of the tab base.
 6. A bobbin according to claim 5wherein a slot is formed in the tab at the root of the pockets enablinglead wires to be passed therethrough and bent to lie in the pockets. 7.A bobbin according to claim 5 combined with a member opposing theretainer tab, said opposing member having fingers with walls shapedcomplemental to the sloped walls of the fingers on said retainer tabthereby to wedgingly hold the lead wires in the pockets.
 8. A bobbinaccording to claim 6 combined with a member opposing the retainer toclamp the wires in the pockets, said oPposing member having fingers withwalls shaped complemental to the walls of the retainer fingers.
 9. In aspool-like bobbin for a motor coil, wherein the bobbin has a core onwhich the coil is wound and a pair of end flanges for retaining the coilwinding, a lead wire retainer tab supported on a flange periphery, saidtab having spaced, flexible fingers projecting axially therefrom andhaving a length parallel to a diameter of the bobbin, each finger havingan inner wall and an outer wall, spaces between adjacent walls of thefingers affording at least two pockets for two lead wires, and selectedwalls of the fingers being sloped so that the tab fingers may be used asguides for an opposing member having complemental fingers thereby toencapsulate the wires on four sides.
 10. A bobbin according to claim 9wherein the tab has a slot through which may be extended the lead wiresattached to the ends of the coil.
 11. A bobbin according to claim 9wherein the tab fingers are flexible.
 12. A bobbin according to claim 10wherein the tab fingers are flexible.
 13. In a bobbin for a motor coil,the bobbin having a core to be wound with a wire and having a pair ofspecial end flanges attached to the core for retaining the winding: awire retainer tab attached to one of the flanges and lying substantiallyin the plane thereof, said tab having spaced fingers defining pocketsfor receiving lead wires each having end attached to a respective end ofthe coil winding, said pockets extending parallel to the plane of thetab, said tab having a slot therein communicating with the root of thepockets whereby the lead wires attached to the coil winding may be bentin one direction incidental to being extended through the slot and bentin another direction incidental to being placed in the pockets.
 14. Abobbin according to claim 13 wherein selected fingers have sloped wallsfor guiding complemented fingers of an opposing member to capture thewires in four-sided pockets.
 15. A bobbin according to claim 14 whereinthe tab fingers are flexible thereby to crimp the wires in thefour-sided pockets.